A valve timing control device is known that, in addition to a lock mechanism for holding the relative rotational phase of a driven-side rotating member relative to a driving-side rotating member at a predetermined phase (a locked phase), includes a restriction mechanism, configured of a restriction recess formed in the driven-side rotating member and a restriction member that is provided in the driving-side rotating member, that is capable of extending into/retracting from the restriction recess.
For example, the valve timing control device disclosed in PTL 1 includes a restriction mechanism configured of a restriction member 5 and a restriction recess 52. Providing the restriction mechanism makes it possible to operate the lock mechanism after the relative rotational phase of the driven-side rotating member relative to the driving-side rotating member has been restricted to a set range, which has an advantage in that it is easier to achieve a locked state.